A part-mounting system includes a solder printing portion made up of a solder printer that prints a substrate with solder and a part-mounting portion made up of one or a plurality of part-mounting machines that mount parts on the substrate printed with solder by means of the solder printing portion. The substrate having finished undergoing part-mounting in the part-mounting portion is sent to a reflow furnace, where the substrate undergoes solder reflow. The substrate having finished undergoing solder reflow is subjected to appearance check. A repair-requiring location found through the appearance check is manually repaired by a worker, like an operator (see; for instance, Patent Document 1). The word “repair-requiring location” includes a defective location caused as a result of a part being mounted outside a target mounting position, as well as including a location caused as a result of a part mounted at a target mounting position on a substrate needing reset because of its defective mounted state.